Infection of human embryonic kidney cells with adenovirus type 12 results in the induction of damage at specific (17q21-22, lp36, 1q21, and lq42-43) and random sites in the cellular chromosomes. A previous study by Durnam et al. (D. M. Durnam, P. P. Smith, J. C. Menninger, and J. K. McDougall, Cancer Cells 4:349-354, 1986) indicated that the expression of viral early region 1 (El) is sufficient for the induction of damage at band 17q21-22. In the present report we used an adenovirus type 12-adenovirus type 5 recombinant with ElA hybrid sequences as well as viruses with mutations in the adenovirus type 12 E1B genes to map adenovirus type 12 El functions involved in the induction of genetic damage. Our results show that the expression of the ElA proteins is not sufficient for this effect. On the other hand, mutations within the ElB 55-kilodalton protein but not the ElB 19-kilodalton protein affect the ability of the virus to induce both specific and random chromosomal damage.
Sulfogalactosylglycerolipid (SGG) is the major mammalian male germ cell glycolipid and has been implicated in sperm/egg binding. Mycoplasma pulmonis, a species of Mollicutes, is associated with male infertility in rodents. Purified SGG incubated in the presence of M. pulmonis was enzymatically degraded by both desulfation and deacylation. Desulfation occurred primarily at alkaline pH, and deacylation also increased with increased pH, indicating that these represent novel enzymatic activities. Digestion was facilitated, but not dependent on, the presence of detergent. Rat spermatozoa exposed to M. pulmonis showed a reduction in SGG content which was particularly marked for cauda (mature) spermatozoa. With the aid of tlc overlay binding procedure, intact M. pulmonis were found to bind specifically to sulfated glycolipids and thus SGG may provide the cell membrane receptor for this organism. The topology of mycoplasma binding to rat sperm was consistent with the known topology of sperm SGG. The reduced binding (and subsequent digestion) of caput spermatozoan SGG correlates with the membrane colocalization of SGG and its endogenous binding protein at this stage. Separation of SGG and its binding protein during epididymal sperm maturation appears to facilitate M. pulmonis binding to and digestion of cauda sperm SGG. The binding and degradation of the sperm SGG by M. pulmonis may play a role in the induction of infertility which follows infection with these organisms by interfering in sperm/egg receptor recognition.
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